A short explanation of RAW to the uninitiated - RAW simply means data direct from the sensor's analog to digital converter (in the case of the D2H 12 bits per pixel) which hasn't been processed in any way. The actual RAW file written to the storage card consist of a header which contains the current camera settings (parameters, exposure, white balance selection etc.) followed by this RAW data itself. The D2H writes RAW files in Nikon's .NEF format which has a compression option delivering RAW files under 4 MB in size. RAW is considered to be 'the digital negative' as it represents the unaltered image data directly as it was captured and can therefore be processed in many different ways.
Unfortunately there is no industry standard for RAW (lots of reasons for this, not least of which are the variances in sensor design and image processing). This means you can't view RAW files in most photo applications like you can with JPEG (although more and more are adding specialized RAW support).
To convert RAW images you have an expanding range of options, supplied with the D2H is the free Nikon Viewer 6.1 which has basic RAW conversion with digital exposure compensation and white balance adjustment. There is also the excellent Nikon Capture 4.0 which provides very advanced RAW conversion, a 30 day trial of this is included with the D2H. Third party RAW conversion tools include Adobe Photoshop CS (although it doesn't yet officially support the D2H) and Phase One's Capture One (again official D2H support coming soon).
JPEG vs. RAW (Nikon View Editor) vs. RAW (Nikon Capture Editor)
Below are two 100% crops taken from images shot within seconds of each other. The first crop is from a Large / Fine JPEG straight from the camera, the second from a RAW converted to TIFF using Nikon View 6.1 Editor, the third from the same RAW converted to TIFF using Nikon Capture 4 Editor.
Nikon View Editor bug or Nikon Capture Editor bug?
First of all their appears to be a bug in Nikon Capture Editor and Nikon View Editor related to sharpening. The resolution chart was taken with a Sharpening setting of 'Auto'. Nikon View Editor appears to interpret this as a sharpening level of 'None', Nikon Capture Editor interprets this as a sharpening level of 'Normal'. The camera appears to apply a sharpening level of 'Low'.
Thus to make the comparison worthwhile I had to forced both Nikon View Editor and Nikon Capture Editor to use the Sharpening level of 'Low' (which appears to then match the camera output).
|JPEG||RAW (Nikon View Editor)||RAW (Nikon Capture Editor)|
As you can see both Nikon View Editor and Nikon Capture Editor deliver images which are to all intents and purposes identical. This is hardly surprising as Nikon View Editor will use the same RAW conversion engine as Nikon Capture Editor. Both converted RAW images deliver slightly more resolution and certainly less artifacts than the JPEG original from the camera.
Adobe Photoshop CS vs. Nikon Capture Editor
Disclaimer: Adobe Photoshop CS does not officially support the Nikon D2H although it will open D2H .NEF files. As you can see from the crops below Adobe Photoshop CS can't (at the moment) match Nikon Capture Editor for absolute resolution, nor elimination of artifacts, however I do prefer the crisp appearance of the numbers on the chart and the lack of sharpening halos. Lets hope Adobe will add full support for D2H RAW soon.
|RAW (Adobe Photoshop CS)||RAW (Nikon Capture Editor)|
RAW vs. JPEG appearance
Below are a set of crops from the same shot taken in JPEG and RAW modes. The crops shown are from a TIFF converted, linked from the thumbnail is an 'Excellent quality' JPEG. The RAW converted image appears to be slightly sharper with better contrast, that said there don't appear to be any color or resolution advantages (with a default conversion).
|JPEG||RAW (converted using Nikon Capture Editor)|
|1,831 KB||4,125 KB|
Overall Image Quality / Specifics
As we would expect from Nikon's new flagship professional digital SLR the D2H's image quality is on the whole excellent. It maintains that 'SLR like' clean look that we first saw from the D1 and which has remained the benchmark for image delivery on all digital SLR's since. There's just something about the image processing and wider dynamic range which gives digital SLR images a far more film like appearance.
The D2H delivers about as much resolution as we could expect from a four megapixel sensor and it can be as smooth / without sharpening artifacts or sharp / with some artifacts as you prefer thanks to a wide range of image processing options in-camera. Add RAW into the mix and you clearly have a wide range of image 'finishes' to suite your particular output medium.
Color balance was very good, we got the best color shooting in Color Mode II (Adobe RGB) which of course maintains the maximum color gamut. Tonal range was good, the D2H exhibiting at least as much dynamic range as the camera it replaces and tending towards a lower contrast image when using the 'Auto' tone setting. I wasn't overly impressed with automatic white balance, especially in artificial light, I had expected the hybrid sensor setup to work better.
One slight disappointment must be the performance of the LBCAST sensor in terms of noise. Our noise tests show that the camera isn't as 'clean' at its lowest sensitivity (ISO 200) as the CMOS based Canon EOS-10D (ISO 200), nor the CCD based EOS-1D (ISO 200). From ISO 400 to 1600 the D2H appears to be a match for the EOS-1D but isn't as clean as the EOS-10D at ISO 1600. Remember also that the D2H's pixel area is quite a bit larger than that of the six megapixel Canon CMOS sensor. We had hoped to see low noise at high sensitivity from Nikon's LBCAST technology.